Plastic drinking cups



July 13, 1965 R. BARON 3,194,468

PLASTIC DRINKING CUPS Filed June 11, 1962 FIG. 1

INVENTOR RONALD BARON BY%%TMZZZZ7/ ATTOR N EYS United States Patent3,194,468 PLASTIC DRINKHQG CUPS Ronald Baron, Agincourt, Ontario,Canada, assignor, by mesne assignments, to Somerville IndustriesLimited, London, Ontario, Canada Ihled June 11, 1962, Ser. No. 201,643 2Claims. (Cl. 229-15) This invention relates to thin-walled plasticdrinking cups particularly of the disposable variety.-

Disposable drinking cups formed from processed paper have been used formany years but, of course, due to their nature and yieldably they arenot as preferable to use as more rigid drinking container. Due tomaterial advances in the plastic industry, it has now been possibleeconomically to provide disposable thin-walled drinking cups formed fromplastic. However, while the plastic cup is much more desirable from thepoint of View of its rigidity compared to paper cups and while both havethe disadvantage that heat is readily transferred through them when theycontain hot beverages, the more dense thin-walled plastic tends totransfer heat to the users hand a little more quickly as to bring abouta disadvantage in this respect. A proposal has previously been made toform a cup of this kind, having a smooth interior surface, with externalclosely spaced apart protruding ribs having intervening valleys with aview to reducing its heat transferring characteristics to the hand ofthe user by causing the contacting surface of the users hand to engagethe peaks of said ribs while spanning the valleys formed therebetween,thus to provide air circulating heat dissipating channels. While such aproposal has had some effect towards achieving this objective, it hasnot been possible to provide ribs of sufficient depth in such athin-walled product to achieve the desired results.

The present invention avoids the difiiculties previously encountered inattaining the objective while providing additional advantages over theprior proposals. Accord-ing to the present invention, I provide athin-walled plastic cup defined by a circumferential side wall and abase wherein the side wall is corrugated to form on the inside andoutside surfaces a plurality of corresponding closely andcircumferentially spaced longitudinally extending substantially parallelribs and valleys of substantial depth, the spacing between the ribsbeing sufficiently close as to cause the contacting surfaces of theusers hand to engage the peaks of said ribs while spanning theintervening valleys and wherein said valleys form heat dissipating aircirculating channels.

The invention will be clearly understood by reference to the followingdetailed specification taken in conjunction with the accompanyingdrawings.

In the drawings:

FIG. 1 is a perspective illustration of the cup of the presentinvention.

FIG. 2 is a longitudinal section taken along the line 22 of FIG. 1; and

FIG. 3 is a fragmentary transverse section through the wall of the cuptaken substantially along the line 3-3 of FIG. 2.

Referring to the drawings, A indicates a thin-walled thermo-plastic cupof generally conventional outline formed by injection molding andproviding a hollow open topped body defined by a circumferential sidewall joined by an integral base 11. The side wall 10, as shown, is of acorrugated form indicated at 12 as to form on the inside and outsidewalls a plurality of corresponding ribs and valley 13 and 14,respectively, and 15 and 16, respectively (FIG. 3), which ribs andvalleys are disposed longitudinally of the cup body and are spacedddAfib Patented July 13, 1965 apart circumferentially of the cuprelatively closely such that this ribbing forms a gripping area so thatthe contacting surfaces of the users hand engage the peaks of theexternal ribs while spanning the intervening external valleys, thus toprovide by way of the external valleys practical heat dissipating aircirculating channels. By forming the ribs as corrugations so they occuron both the inside and outside of the cup wall, I am able to achievereasonably deep valleys as to produce practical air circulating channelswhereas in addition, the formation gives the cup a degree of flexibilitysuch as to avoid possibility of fracture in normal use which can occurin a thin-walled stiffer body. In addition, it is possible to produce acup from less material, thus achieving an economic advantage as well.

I prefer to form the external ribs in such a way as to provide a thickerwall at the apex thereof as indicated at 17 in FIG. 3. This tends toreduce the heat conductivity and tends to strengthen the structure butwhat is of more importance, the formation of these thicker apices hasthe additional important eflFect of making it possible to produce a verythin-walled cup while changing the direction of flow of the plastic forthe thinner sections, thus obtaining a reorientation of the plasticwhich adds to the strength and physical properties of the article. Thisis achieved through the fact that as the hot fluid plastic is injectedinto the mold it follows the line f0 least resistance, i.e. the deepercavities for the thicker section forming the thick apices of the ribsand then tends to expand c-ircumferentially to fill the thinnersections. Consequently, a much stronger cup is produced whereas if thelarger apices in the mold were not employed, it would be necessary toprovide for a thicker walled cup to achieve a structure of thischaracter. Therefore, a substantial saving in plastic material isattained. It is preferred to form the wall of a thickness between .010"and .020" and to provide a thickness between .035 and .040" at theapices of the external ribs. However, it should be understood that whilethe preferred form of construction employs thick apices as described,the invention in its broadest aspect is not limited to this mostpractical formation and would apply to a thicker walled corrugated cupwhere this may be of practical use.

In addition to the advantages above defined, three further advantagesare achieved in a cup of this formation since it permits better nestingof the cups for packaging and storage purposes, whereas from the pointof view of health and the ditficulty of washing an internally groovedcup, it discourages re-use of improperly washed cups which would not bedetected in the plainer variety. Moreover, it will help to discouragemobile beverage dispensers from re-using cups to dispense more of thebeverage than would normally be accounted for by the number of cups thathe is issued when starting out on his sales tour. This is so becauseeven if he retrieves some of the used cups and attempts to rinse themfor re-use, there will always be some indication by way of the internalvalleys of its previous use, leading to the detection of such animproper practice.

Finally, and of particular importance, is the fact that the cupconstructed according to the present invention can be manufacturedfaster than ordinary varieties through the fact that due to thecorrugations, a greater surface area is exposed to the cooling effect ofthe dies so that the forming cycle can be shortened over that of theordinary variety as to thus increase speed of production. Consequently,measured by the sum of the advantages, it is clear that the presentinvention achieves a marked advance in the art.

and external ribs and valleys extending in the direction;

of the longitudinal axis of said body, said external ribs terminating inpeaks which form, a gripping area for the hand of a user, the spacingbetween the ribs being suificiently close as to cause the contactingsurfaces of the users hand to engage the peaks of said ribs while span-'ning the intervening external valleys, said'external valleys formingheat-dissipating air circulating channels, said ribs and valleys beingformed by converging portions of said side Wall, said valleys on theinside of said side wall being augmented with plastic where the portionsof the side wall converge to thicken and strengthen the ribs on theoutside of said side wall.

2. A moulded plastic cup as claimed in claim 1, in which the thicknessof the side wall adjacent where the corrugations thereof coverage toform said valley-on the inside of said side wall is between .010" andi020 and the thickness of the external ribs attheir peaks is between.035" and '.040".

References Cited by the Examiner UNITED STATES PATENTS D. 159,599 8/50Chaplin. a

' 549,394 11/95 Presnell 21511.3 2,115,654 4/38 Swofiiord. 215l00.5 X2,493,380 1/50 Bailey 215--11.3 2,731,056 1/56 -Anson.. t 2,799,435 7/57Abplanalp 264-328 X 2,899,110 8/59 Parker i 150-.5 3,001,683 V 9/61Goodwin et a1. 229-25 3,045,887 7/62 Caine p i229-l.5 3,073,025 2/63Welshon 229-15 3,079,027 2/63 Edwards 220--9 3,082,900 3/63 Goodman220-15 3,085,730 4/63 Fibish 229--1.5

THERON E. CONDON, Primary Examiner.

1. AN INJECTION MOULDED PLASTIC CUP COMPRISING A HOLLOW, THIN WALLED,OPEN TOPPED BODY, DEFINED BY A CIRCUMFERENTIAL SIDEWALL AND AN INTEGRALBASE, SAID SIDEWALL BETWEEN ITS TGOP AND BOTOM BEING OF CORRUGATED FROMPROVIDING A SERIES OF ALTERNATING SUBSTANTIALLY PARALLEL INTERNAL ANDEXTERNAL RIBS AND VALLEYS EXTENDING IN THE DIRECTION OF THE LONGITUDINALAXIS OF SAID BODY, SAID EXTERNAL RIBS TERMINATING IN PEAKS WHICH FORM AGRIPPING AREA FOR THE HAND OF A USER, THE SPACING BETWEEN THE RIBS BEINGSUFFICIENTLY CLOSE AS TO CAUSE THE CONTACTING SURFACES OF THE USER''SHAND TO ENGAGE THE PEAKS OF SAID RIBS WHILE SPANNING THE INTERVENINGEXTERNAL VALLEYS, SAID EXTERNAL VALLEYS FORMING HEAT-DISSIPATING AIRCIRCULATING CHANNELS, SAID RIBS AND VALLEYS BEING FORMED BY CONVERGINGPORTIONS OF SAID SIDE WALL, SAID VALLEYS ON THE INSIDE OF SAID SIDE WALLBEING AUGMENTED WITH PLASTIC WHERE THE PORTIONS OF THE SIDE WALLCONVERGE TO THICKEN AND STRENGTHEN THE RIBS ON THE OUTSIDE OF SAID SIDEWALL.